package newKe;

import java.util.Scanner;

public class HJ107 {
    /**
     * 计算一个浮点数的立方根，不使用库函数。
     * 保留一位小数。
     */
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        double d = in.nextDouble();

        double left = -2.8;
        double right = 2.8;
        double mistake = 3;
        double re = 0;

        while (Math.abs(mistake)>0.01){
            double mid = (left+right)/2;
            System.out.println("mid = "+mid);
            double res = Math.pow(mid,3);
            mistake = res - d;

            if(res>d){
                right = mid;
            }else {
                left = mid;
            }
            re = mid;
        }



        System.out.printf("%.1f",re);
    }
}
